Resumen:

It is usually difficult to compare different designs of Positron Emission Tomography (PET) small-animal scanners because of the disparity of measurements protocols. In this work we compare two commercial PET scanners installed at ClEMAT (Madrid, Spain): the ClIt is usually difficult to compare different designs of Positron Emission Tomography (PET) small-animal scanners because of the disparity of measurements protocols. In this work we compare two commercial PET scanners installed at ClEMAT (Madrid, Spain): the ClearPET and the rPET-I, using an
assessment procedure that fulfilled the recommendations of the
new NEMA NU 4-2008 standard to evaluate small animal PET
systems, including spatial resolution, sensitivity, scatter fraction and count losses studies. The scanners evaluated have significant geometrical differences, like the axial field of view (110 mm on
ClearPET versus 45.6 mm on rPET-l), the configuration of the
detectors (one pair of planar blocks on rPET-I, versus whole ring
detectors on ClearPET) and the use of an axial shift between
ClearPET module detectors. Our experiments showed a FWHM
(FOV center, averaged over the three axes) of 1.98 mm for the
rPET-1 and 2.15 rom for the ClearPET, with a small variation
across the transverse axis on both scanners «1 rom). The absolute
sensitivity was 1.0% per detector pair for rPET-I and 4.70/0 for
ClearPET. Regarding count losses studies, the obtained peak
NEC rate is 73.4 kcps at 0.51 MBq/ml for the ClearPET and 29.2
kcps at 1.35 MBq/ml for the rPET-1, considering a NEMA
mouse-like phantom.[+][-]